3H/3He ratio as a probe of the nuclear symmetry energy at sub-saturation densities

Yongjia Wang; Chenchen Guo; Qingfeng Li; Hongfei Zhang

doi:10.1140/epja/i2015-15037-8

2022 Impact factor 2.7

Hadrons and Nuclei

Eur. Phys. J. A (2015) 51: 37
https://doi.org/10.1140/epja/i2015-15037-8

Regular Article - Theoretical Physics

³H/³He ratio as a probe of the nuclear symmetry energy at sub-saturation densities

Yongjia Wang¹^,2, Chenchen Guo¹^,3, Qingfeng Li¹^* and Hongfei Zhang²

¹ School of Science, Huzhou University, 313000, Huzhou, P.R. China
² School of Nuclear Science and Technology, Lanzhou University, 730000, Lanzhou, P.R. China
³ College of Nuclear Science and Technology, Beijing Normal University, 100875, Beijing, P.R. China

^* e-mail: liqf@hutc.zj.cn

Received: 28 July 2014
Revised: 8 December 2014
Accepted: 6 March 2015
Published online: 26 March 2015

Abstract

Within the newly updated version of the ultra-relativistic quantum molecular dynamics (UrQMD) model in which the Skyrme potential energy-density functional is introduced, the yield ratio between ³H and ³He clusters emitted from central ⁴⁰Ca + ⁴⁰Ca, ⁹⁶Zr + ⁹⁶Zr, ⁹⁶Ru + ⁹⁶Ru, and ¹⁹⁷Au + ¹⁹⁷Au collisions in the beam energy range from 0.12 to 1 GeV/nucleon is studied. The recent FOPI data for the ³H/³He ratio are compared with UrQMD calculations using 13 Skyrme interactions (all exhibiting similar values of iso-scalar incompressibility but very different density dependences of the symmetry energy). It is found that the ³H/³He ratio is sensitive to the nuclear symmetry energy at sub-saturation densities. Model calculations with moderately soft to linear symmetry energies are in qualitatively agreement with the ³H/³He ratio data of the FOPI Collaboration. This result is in line with both the recent constraints on the low-density symmetry energy available in the literature and our previous results for the high-density symmetry energy obtained with the elliptic flow of free nucleons and hydrogen isotopes as a sensitive probe.